HESI A2 Anatomy and Physiology 2023

Correct Answer: A

Rationale: The correct answer is A: Cerebellum. The cerebellum is responsible for controlling balance and coordination. It receives information from the sensory systems, such as the inner ear and visual system, and integrates this information to coordinate smooth movements. The cerebrum (B) is mainly involved in higher brain functions like thinking and problem-solving. The medulla oblongata (C) controls vital functions such as breathing and heart rate. The brainstem (D) is responsible for basic life functions like breathing and consciousness. Thus, the cerebellum is the specific region of the brain that directly controls balance and coordination.

Correct Answer: B

Rationale: The correct answer is B: Hinge joint. The elbow joint is a hinge joint because it allows movement in one plane, similar to a door hinge. It primarily allows flexion and extension movements. A ball and socket joint (A) allows a wider range of motion in multiple planes. A pivot joint (C) allows rotation around a central axis. A saddle joint (D) allows movement in multiple directions with a greater range of motion compared to a hinge joint.

Correct Answer: A

Rationale: The correct answer is A: Cerebellum. The cerebellum is responsible for balance and coordination as it receives sensory information from the inner ear and muscles to control movement. It coordinates muscle actions and maintains posture. The cerebrum (B) is responsible for higher brain functions, the medulla oblongata (C) controls basic life functions like breathing and heart rate, and the hypothalamus (D) regulates body temperature, hunger, and thirst. Thus, the cerebellum is the most appropriate choice for balance and coordination.

Correct Answer: C

Rationale: The correct answer is C: Cortisol. Cortisol is a hormone released by the adrenal glands in response to stress. It helps regulate metabolism, immune response, and blood pressure during stressful situations. Insulin (A) is involved in regulating blood sugar levels, not the stress response. Adrenaline (B) is also known as epinephrine and is involved in the fight-or-flight response, which is part of the stress response. Melatonin (D) is a hormone that regulates sleep-wake cycles and is not directly related to the stress response.

Correct Answer: B

Rationale: The correct answer is B: Thyroid gland. The thyroid gland produces hormones such as thyroxine (T4) and triiodothyronine (T3), which regulate metabolism by controlling the body's energy production and utilization. The pituitary gland (A) regulates various other hormones but not specifically metabolism. The adrenal gland (C) produces hormones like cortisol and adrenaline, which are involved in stress response, not metabolism. The pineal gland (D) produces melatonin, which regulates sleep-wake cycles, not metabolism. Therefore, the thyroid gland is the correct answer as it directly controls metabolic functions.